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Multi-operation punching of sheet metal

Shearing process that removes and/or molds flat material.

Illustration of Multi-operation punching of sheet metal

The process

When punching, the workpiece is placed on the lower tool, the die [1]. The upper tool, the punch [2], is pressed against the workpiece with an applied pressing force. Depending on the design of the workpiece, one or more subsequent strokes is needed.

A scraper [3] ensures that the plate is detached from the punch if it gets stuck and is lifted up after the strike.

There are a variety of punching tools that can do everything from cutting straight lines and creating pre-tapped holes to Engraving and carrying out minor bending operations.

To punch out a hole the material is subject to shearing between the punch and die. During the punching process material is displaced and then loosen completely by material failure. This gives both the punched detail and bore, the typical cut surface seen in punching operations i.e., smooth surface [4] where the material has slipped and a rougher surface [5] where the failure occurs.

In cases where the tools are designed to carry out compression forming, the sheet is deformed by plastic deformation.

Usually the workpiece is moved while the tools retain their position.